The invention relates generally to medical implants used to regulate the flow of fluids within the body. The invention may be applied, for example, to ophthalmic implants for treatment of glaucoma. The invention also relates to delivery devices for implanting such implants, to methods of implanting such implants, and to methods of manufacturing such implants.
Medical implants used to regulate the flow of fluids within the human body are known and used. One application for the use of such implants is in the treatment of glaucoma. Typical ophthalmic implants utilize drainage tubes for the release of aqueous humor from the eye to relieve the intraocular pressure (IOP).
Several disadvantages have at times been associated with prior implants. For example, implants using valve mechanisms to regulate fluid flow have risked malfunction due to defects in and/or failure of such valve mechanisms. Depending on such factors as the site of implantation, some implants have tended to clog while in use due to tissue covering the inlet end or the outlet end of the drainage tube. In addition, prior implants at times have required insertion operations that are complicated, costly, and time-consuming, for example requiring suturing of the implant once it is in place.
The assignee of this patent application is also the assignee of other patents and patent applications describing and illustrating implants directed at overcoming some of the drawbacks associated with prior implants, as well as delivery devices for such implants, methods of using such implants, and methods of manufacturing such implants.
For example, implants, delivery devices, methods of use, and methods of manufacturing are described and illustrated in U.S. Pat. Nos. 5,868,697 and 5,702,414, both of which are owned by the assignee of this application, and both of which are hereby expressly incorporated by reference into this application.
Further examples of such implants, delivery devices, methods of use, and methods of manufacturing are also described and illustrated, in U.S. Pat. No. 6,203,513 filed Nov. 20, 1997, which is also owned by the assignee of this application, and which is also hereby expressly incorporated by reference into this application.
One object of the invention is to provide a flow regulating implant and an associated delivery device that enable the implant to be inserted in a relatively simple and efficient procedure.
In one embodiment in accordance with the invention, an implant having a tube for permitting fluid flow has an outer flange at the outlet end and one or more retention projections near the inlet end. An introducer or delivery device for implanting the implant has a central bore for accommodating the implant during the implantation procedure. The implant and delivery device are designed so that when the implant is loaded in the delivery device, the retention projection or projections of the implant protrude from the delivery device to act as a hook or hooks during the procedure.
In accordance with a method of using the implant and delivery device according to an embodiment of the invention, the implant is loaded in the delivery device with the retention projection protruding from the delivery device. The delivery device and implant then penetrate the tissue through which drainage is desired, for example, the sclera of an eye. Once the retention projection has fully penetrated through the tissue, the delivery device is withdrawn. The retention projection acts as a hook engaging the inside surface of the tissue, causing the implant to stay implanted in the tissue when the delivery device is withdrawn.
The retention projection may be made, for example, of an elastic material, so that it is able to be flexed inward against the tube of the implant during penetration through the tissue. Alternatively, the retention projection may be designed to lie initially relatively flat against the tube for easier penetration and to prevent tearing of the tissue, with a mechanism for extending the retention projection outwardly when the implant is implanted.
Another object of the invention is to provide a simple and efficient method of manufacturing a flow regulating implant. In a method for manufacturing an implant according to an embodiment of the invention, the device may be molded out of a suitable material, for example, silicone. To provide the tube passage of the implant, a thin wire may be used during the molding process. The implant alternatively may be constructed out of stainless steel or any other suitable material.
A further object of the invention is to provide a flow regulating implant with beneficial flow characteristics. Thus, the implant may have various mechanisms for changing the configuration of the flow path. For example, a flow controlling rod or other obstruction may be placed in the tube passage for changing the dimensions within the tube passage. This rod or obstruction may be temporary. For example, it may be made of absorbable (biodegradable) material that is eroded and absorbed. Alternatively, it may be constructed in such a way that it may be removed from the tube passage or advanced into the tube passage at a period of time after implantation. For example, one or more strands, such as sutures, may be placed in the tube passage and withdrawn or advanced by a physician as desired at a later time or times.
An implant according to the invention has other applications aside from the field of intraocular implants. For example, the implant may be used for drainage of a hydrocele sac, regulating flow between the hydrocele sac and the subcutaneous scrotum. Persons of ordinary skill in the art will appreciate that other applications of an implant in accordance with the invention are possible, as are various modifications of the embodiments described herein, without departing from the scope of the invention as defined in the claims.